Folding bikes have been around for a while now, here is an interesting concept from designer Victor M Aleman, for a folding bike where everything including the wheels can been collapsed, the Folding Urban Bike Concept.

The Wheel is composed by six modules, each one has a double pivot in the joints, this allows the wheel to fold and become smaller, the spokes are contained in the inner structure of the wheel, when you unfold the system, the spokes rotate to the center of the mechanism where it attach to the center of the wheel.

It certainly looks like an interesting design, mind you I suspect people like me would take quite some time to work out how to unfold it.

Tuvie via Treehugger, Dvice